It is often helpful to show the back of a brass plate fragment, so we ID-helpers can know whether its construction is simple stamped sheetbrass, or solder-filled sheetbrass, or solid-cast brass. Which is it?
Since nobody else has answered your request, on your behalf I plowed through the entire section on US Navy, Marines, Coast Guard, etc, in the "American Military Belt Plates" book by O'Donnell & Campbell. There seems to be no match there for your find. The only plate which has a wreath's leaves below the anchor is a thick solid-cast brass plate, made for use by the US Revenue Cutter Service from 1890 to 1915. But as I indicated above, it's not an exact match.